Analog Devices Inc. AD8643ARZ-REEL7

Overview

AD8643ARZ-REEL7 from Analog Devices is a quad-channel, low-power, rail-to-rail output, precision JFET-input operational amplifier optimized for high-impedance sensor interfaces and precision analog signal conditioning. It delivers 250 µA max supply current per amplifier, 1 pA max input bias current, 750 µV max offset voltage, and operates from 5 V to 26 V single supply or ±2.5 V to ±13 V dual supply - enabling use in battery-powered photodiode amplifiers and industrial current-sensing circuits.

For engineers reviewing the AD8643ARZ-REEL7 datasheet, AD8643ARZ-REEL7 pinout, AD8643ARZ-REEL7 application, or AD8643ARZ-REEL7 equivalent, key selection criteria include ultra-low input bias current for high-Z source buffering, rail-to-rail output swing into 10 kΩ loads, unity-gain stability with >500 pF capacitive drive capability, and guaranteed operation across −40°C to +125°C for industrial control and medical instrumentation.

Technical Context

The AD8643ARZ-REEL7 implements a JFET-input stage delivering femtoampere-level input bias current and low input capacitance (typically 1.5 pF), making it suitable for photodiode transimpedance amplifiers and precision charge integration. Its fully differential input stage supports common-mode input range from V− to (V+ − 3 V) under single-supply conditions.

Internally compensated for unity-gain stability, the amplifier maintains ≥50° phase margin with 2.5 MHz gain-bandwidth product and 2 V/µs slew rate at 5 V supply. Output stage is rail-to-rail, achieving VOH ≥ 4.94 V and VOL ≤ 0.05 V at IL = 1 mA over full temperature range.

Key Specifications

Pinout & Package

AD8643ARZ-REEL7 is housed in a 14-lead SOIC (R-14) package with exposed pad not connected internally; pin 1 is marked by notch or bevel. The package measures 8.75 mm × 4.00 mm × 1.75 mm and is RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision op-amp applications.

Compared with OPA2182IDR and LT6015IMS8#PBF, AD8643ARZ-REEL7 uniquely balances femtoampere input bias, rail-to-rail output, and sub-250 µA quiescent current in a quad configuration - making it irreplaceable for space-constrained, battery-operated precision analog front-ends requiring four independent high-Z channels.

Availability

AD8643ARZ-REEL7 is available at Aetrix Electronics and suitable for photodiode amplifiers, precision current sensing, and medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD8643ARZ-REEL7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA.

The AD864x family was designed specifically for precision, low-power, high-input-impedance analog signal conditioning in battery-operated and thermally constrained industrial and medical systems - emphasizing JFET input architecture, rail-to-rail output, and extended temperature qualification.

FAQ

What is the maximum capacitive load the AD8643ARZ-REEL7 can drive while remaining stable?

The AD8643ARZ-REEL7 is specified to remain stable with capacitive loads exceeding 500 pF, as confirmed in the datasheet's Typical Performance Characteristics section (Figure 36–37). This eliminates the need for series isolation resistors when driving ADC inputs or passive RC filters, provided layout minimizes parasitic inductance in the output path. Stability is maintained across all four channels simultaneously under these conditions.

Does the AD8643ARZ-REEL7 support true rail-to-rail input common-mode range?

The AD8643ARZ-REEL7 does not support rail-to-rail input; its common-mode input voltage range extends from V− to (V+ − 3 V) under typical operating conditions. For example, with VS = 5 V, the usable input range is 0 V to 2 V. This limitation is inherent to its JFET input stage architecture and is explicitly documented in Table 1 and Table 2 of the datasheet.

How many operational amplifiers are integrated in the AD8643ARZ-REEL7?

The AD8643ARZ-REEL7 integrates four independent precision operational amplifiers in a single 14-lead SOIC package. Pin configuration diagrams (Figure 5) confirm dedicated inputs and outputs for channels A, B, C, and D, with shared V− and no internal connection on pin 8 - enabling compact multi-channel analog signal conditioning without discrete device duplication.

Is the exposed pad on the AD8643ARZ-REEL7 package electrically connected?

No - the AD8643ARZ-REEL7 uses a 14-lead SOIC (R-14) package, which does not feature an exposed thermal pad. Exposed pads are only present on the LFCSP variant (AD8643ACPZ-REEL7). The R-14 package relies on standard lead-frame thermal conduction; no special PCB copper attachment is required beyond standard SOIC soldering practices.

What is the guaranteed minimum open-loop gain of the AD8643ARZ-REEL7 at 25°C?

At TA = 25°C, VS = 5 V, RL = 10 kΩ, and VO = 0.5 V to 4.5 V, the AD8643ARZ-REEL7 guarantees a minimum large-signal voltage gain (AVO) of 80 V/mV (i.e., 80,000 V/V) as specified in Table 1. This ensures <12.5 ppm gain error in unity-gain buffer configurations and supports precise closed-loop gain accuracy in instrumentation-grade circuits.